In this concise, scholarly work, Mohammad Ali Shomali outlines the distinguishing features of the Twelver Shi‘a school of Islamic thought, which is based on the teachings of the Household of the Prophet. He focuses on the textual sources of Shi‘i thought and the leading doctrines of Shi‘ism – both those which are shared with other Muslims and those that are unique to Shi‘ism, such as the emphasis on divine justice, the imamate, and the infallibility of the Imams. Concluding with a useful survey of Shi‘a demographics, devotional practices, and holy sites, this readable work answers many common questions about the origins, history, and beliefs of Shi‘i Muslims with an emphasis on spirituality and rationality. Timely and relevant given the focus on Shi‘i Muslims in the world media today.